The music CD in general bears a table of contents (TOC) listing the tunes prerecorded thereon and the addresses of the locations in which they start. The prerecorded tunes are usually referred to as tracks according to common CD parlance, and the serial numbers assigned to the tunes as track numbers. These familiar CD terms, “tracks” and “track numbers,” will be used in some cases in places of prerecorded tunes and their serial numbers hereinafter in this specification. The track number must be specified for playback of any desired one of the tracks on the CD. The starting address of any specified track is ascertainable from the TOC, enabling the optical pickup to be positioned at the beginning of that track for immediate commencement of playback. Two or more different desired track numbers may be input in a desired sequence for sequential playback of the desired tunes.
The TOC of the CD commercially available today lists only the starting address of each recorded tune. The existing TOC has therefore not enabled the user to choose some desired part of each tune for playback or for rerecording on different media such as recordable CDs (CD-Rs), re-writable CDs (CD-RWs), so-called minidisks (MDs), or digital audio tapes (DATs). Of course, the user may manually play back only part of each tune, but difficulties have been involved in playing back the exactly desired part of the tune. It has not been possible, either, to divide each track into two or more parts, to join two or more tracks, to skip or move a track or tracks, or to otherwise edit the prerecorded tunes, by making use of the TOC.
It has been suggested to incorporate into the CD player an additional memory dedicated to partial playback of any desired part of each tune. The user is to write on the memory what part of which tune he or she desires to be played back. This additional memory has to be of in-conveniently large capacity for storing all the pertinent data of the recordings.
The TOC on magneto-optic MDs bear the addresses of both beginning and end of each tune recorded thereon, as disclosed for example in Japanese Unexamined Patent Publications Nos. 6-231572 and 8-138352. The editing of the TOC on MDs is therefore far easier than that on music CDs, there being no ending address of the tunes being listed as aforesaid on the TOC of CDs. Hitherto, therefore, no editing of the TOC has been practiced in the case of CDs.
The present invention has it as an object to provide an apparatus for playback of a data storage disk of the type having a series of tunes or like information streams prerecorded thereon, so made that the information streams may be played back in a more versatile way than heretofore.